Scheme 1.

Illustration of viral detection using silicon photonic microring resonators. Microrings functionalized to present antibodies (purple) specific for the virus of interest (blue icosahedron) (a) support optical resonances at particular wavelengths that are extremely sensitive to antigen binding induced changes in the local refractive index. As viruses in a sample bind to the antibodies on the microring, the resonance shifts to longer wavelengths (b), and this shift is monitored in real time (c) to allow quantification of the target virus. In (c) the arrow indicates the time at which the sample is introduced and the * indicates the return to running buffer. (For interpretation of the references to color in this scheme legend, the reader is referred to the web version of the article.)